1. Field of the Invention
The present invention relates generally to computer peripheral equipment and more specifically, to an auxiliary device that facilitates the manual entry of frequently used information into a computer or computer-controlled system.
2. Prior Art
The present invention may be readily distinguished from the known prior art which consists for the most part of the following:
Function keys built into a terminal or computer keyboard where each key generates a fixed code sequence each time it is depressed.
Programmable function keys built into a terminal or computer keyboard where each key generates a user-defined code each time it is depressed.
Non-volatile programmable function keys wherein user-defined code sequences are retained by battery-powered non-volatile memory in the terminal.
Computer software-controlled programmable function keys in which a fixed code generated by each function key on the terminal or computer keyboard is compared to a table of key definitions to initiate the desired character sequence for that key. The intercept program and character sequence table are in the computer memory.
Computer software-controlled keys ("soft" keys) in which the user can allow each key on the keyboard to retain its normal character identity or can reprogram any key to represent a different character or string of characters. When a key is depressed, the computer's operating system or an application program determines whether the standard character code is to be accepted. If it is not to be accepted, the pre-defined character(s) are entered according to a table contained in the computer's memory.
There are several significant disadvantages of function keys on a terminal, a keyboard with programmable function or "soft" keys and programs which intercept keyboard inputs in order to generate pre-defined character sequences. For example, programmable function keys are usually available only on expensive terminals, thus requiring a significantly increased investment by the user in order to obtain programmable function keys. Furthermore, terminals with function keys generally allow only a small number of sequences to be programmed, typically in the range of 10 to 32. Typically, programmable function keys with code storage in the terminal accept a very limited number of characters. For example, one popular terminal provides a total of 256 characters for its 22 function keys. Most prior art terminals with function keys require character sequences to be manually entered each time the terminal is turned on or alternatively, require the generation of an assembly language program or configuration program to store the sequences. Prior art "soft" keys for which the user defines the character sequence for any specific key on the keyboard, are limited to the number of keys on the keyboard and the intrinsic function of each key is lost when it is assigned a sequence. Furthermore, prior art "computer software-controlled" keys require the use of the computer's memory for the interception program and for the storage of the character sequences, thereby reducing the amount of memory available for other programs and data.
The use of "soft" keys and fixed-code keys of the prior art can slow internal operations because the computer must intercept and process each character as it is received to determine whether it is to generate a code sequence.
Prior art separate function key units and configuration programs are usable only with specific brands of popular microcomputers or terminals and therefore are not adaptable to a wide range of terminal/computer combinations. 248 character sequences of up to 8 characters each are programmed into one such computer-specific unit at the factory, or in certain models, can be individually reprogrammed through keys on the unit.
Prior art non-volatile function key embodiments employ either a factory-programmed read-only memory (PROM) or a battery to maintain power for the retention of character sequences in the unit's memory.